Abstract:

All-way stop-controlled (AWSC) intersections have been widely built in the United States for its safety effects and low cost. By law, all drivers are required to come to a complete stop at the Stop bar before entering the AWSC intersections, however, there is lack of study showing how drivers behave at AWSC intersections with real-world driving data. This study explores driver behavior at six rural high-speed (>=40 MPH) AWSC intersections, which tend to be bottlenecks and more risky than urban low-speed ones. It was carried out using naturalistic driving study (NDS) data collected in the Safety Pilot Model Deployment (SPMD) program. The dataset was generated by over 3,000 instrumented vehicles running for two months in greater Ann Arbor, MI area. The data elements include vehicle’s kinematic and position data recorded at 10 Hz rate. Based on the NDS data, vehicle trajectories through these AWSC intersections were rebuilt (Figure 1). This study focuses on analyzing drivers’ behaviors by visualizing their speed and acceleration profiles while approaching and departing these intersections. It was found that when approaching the intersection, most drivers maintained slowly decreasing speeds from 1,000 ft to 500 ft upstream, and then braked hard till near the stop bar, with maximum deceleration at around 9 ft/sec2. However, a complete stop was only observed in less than 15% of the total trips. After entering the intersection, most drivers would sharply accelerate and usually reached normal speeds after about 1,000 ft. This study presents findings about drivers’ “stop” locations relative to the stop bar, the speeds distribution at “stop” location, and the acceleration pattern after entering the intersection, etc. The results should help roadway designers to more realistically assess/expect the drivers’ compliance rate, and optimize the locations of Stop sign and Stop bar for high speed AWSC intersections to achieve better compliance and safety.